a = 10
b = 20
c = 30
print(a < b and b < c)
print(a < b and b > c)

print(a > b or b < c)
print(a < b or b > c)
print(a > b or b > c)

print(not a > b)
print(not a < b)
print(a > b and 10 / 0 == 1) # 短路求值
print(a < b or 10 / 0 == 1)